It is common practice in the design, manufacture, and operation of known absorption refrigeration system arrangements to provide for the purging of so-called non-condensible gases from the system absorber element to the atmosphere. Many of such known systems separate the unwanted non-condensible gases from the apparatus vaporized refrigerant (usually water vapor) at pressures very nearly equal to the system absorber element subatmospheric operating pressure, store the separated gases in an appropriate vessel at or near the separation pressure, and then periodically or continuously operate an included exhaust vacuum pump to vent the collected and unwanted gases to the atmosphere using vacuum pump discharge pressures greater than atmospheric pressure. An example of such systems is the absorption refrigeration system disclosed by U.S. Pat. No. 2,384,861 issued in the name of Roswell and assigned to Servel, Inc. of New York, New York. Other patents assigned to Servel, Inc. and disclosing similar absorption refrigeration apparatus include U.S. Pat. Nos. 2,363,381; 2,367,708 and 2,432,978 issued in the name of Anderson, Jr., U.S. Pat. No. 2,384,860 issued in the name of Thomas, U.S. Pat. No. 2,510,730 issued in the name of Whitlow, and U.S. Pat. No. 2,510,737 issued in the name of Buffington.
Other known absorption refrigeration systems utilize a refrigeration solution pump that pumps relatively weak or dilute absorption refrigeration solution and entrained non-condensible gases from the apparatus absorber low-pressure side to the apparatus generator high pressure side and require that the purging operation be periodically shut down, as in the case of U.S. Pat. No. 4,467,623 to Reimann, if separated and accumulated unwanted, non-condensible gases are to be vented to the atmosphere at system high-side pressures. See also, in this regard, U.S. Pat. Nos. 3,360,950 issued to Osborne and 3,367,135 issued in the names of Greacen et al.
I have discovered that various changes may be made in the construction and operation of a sub-atmospheric absorption refrigeration system to permit the purging of unwanted, non-condensible gases from the system to the atmosphere without having to pump the separated gases as by a separate vacuum purge pump having a discharge pressure above ambient atmospheric pressure, either with such pump being incorporated permanently into the system or being used only when specially connected to the system intermittently as by a service mechanic during the course of a service call. Also, the purge system of this invention may be made to operate either fully automatically or in response to manual control inputs without requiring that operation of the refrigeration system in any respect be inactivated in order to permit the venting of accumulated non-condensible gases to the atmosphere using inherently present system operating pressures which are greater than atmospheric pressure.